Production of menthenes



Patented Sept. 27, 1932 i I UNITED STATES OFFICE WALTER SCHOELLER, OF BERLIN-WESTENDQHANSJORDAN; OF BERLIN-STEGLITZ, AND KARL SCHGLLKOPF, OF DUSSELDOEF-OBERKASSEL, GERMANY, ASSIGNORS TO THE FIRM SGHERING-KAHLBAUM'A. G., 013 BER IN;-GERMANY rnonuorroiv or mmvrnnnns m Drawing. Application filed November 11, 1929, Serial ro .-goe,5o7,a a ii1 Germany nove per 15, 1928 Our invention relates to chemical com- 140C, are not advisable. The temperature pounds and more especially to menthenes and at which hydrogen is first bound had better has for its particular object to provide means not been exceeded. a p i for producing such menthenes. i We have thus obtaineddelta g p-menthene r We have found that by partiallyhydroin good yield. v

genating by catalytic action menthadienes Example having a double bond in the side chain or in the form of a double bonded methylene, there can be obtained menthenes having their doul ble bond in the nucleus. In practicing this process the temperature should be kept as low as possible and preferably not above the point at which hydrogenation commences. CH3 Y In this manner the double bond located out- H side of the nucleus can readily be hydro- 2 e H' CH +H1= H H H CH genated and the absorption of hydrogen will H2 -o 11 3 then cease after one molecule hydrogen is I H (3H3 H I bound or will slow down so remarkably that 1 7 Hz the end point of the desired reaction can 7 E l g readily be ascertained. I; b t h H d In the practice of our invention We may 8 rem treated as proceed for instance as follows: Sen 8 W1 9 erenqe to xa'mple l 2-p-menthene 1s obtained. The reaction oc- Ewample 1 curs according to the equation:

Beta-terpinene is treated at the lowest pos- CH2 H on;

sible temperature and under pressure in the presence of about 1 to 3% of its Weight of a hydrogenation catalyst containing nickel, and which may also be precipitated on a carrier with hydrogen, until the quantity of Sylvestrene is treated with hydrogenas described with creference .to Example 1, and there is obtalned delta-l-m-methene (Lie- 7 occurs according to the equation:

o- -0 0H OCH hydrogen is bound which 1s required for H3 11 Ha 3 H 3 half-hydrogenation. The reaction occurs acbigsAnnalen,ivol. 360, p. ,7 9) The reaction cording to the equation: I l i HipoHs 7 On treating dlpentene as described with l 1 reference to Example 1, carvomenthene is ob- H H2 H H2 tained. The reaction occurs according to H i th t' H y H H y H e equa ion OH 3 OH1 -OH OHa-0-OH; 7 i a a r H +H The temperature to be observed depends H F 2 from the kind of catalyst used, the reaction \H proceeding in some cases at ordinary temv CH 0:011 OH; CH perature. As a rule temperatures above 2 I 3 H a Various changes may be made in the details disclosed in the foregoing specification without departing from the invention or sacrificing the advantages thereof.

I claim 1. The method of producing menthenes comprising treating a liquid menthadiene havin a double bond outside the nucleus at a moderately elevated temperature in the presence of a hydrogenation catalyst containing nickel with hydrogen, until one molecule of hydrogen is bound.

- 2. The method of producing menthenes comprising treating a liquidmenthadiene having a double bond outside thenucleus at a moderately elevated temperature under pressure in the presence of a hydrogenation.

catalyst containing nickel with hydrogen, until one'molecule of hydrogen-is bound. The method of producing menthenes comprising'treating a liquid menthadiene having a double bond outside the nucleus'in the presence of an hydrogenation catalyst containing nickel with hydrogen, until one molecule of hydrogen is vhound, care being taken to avoid heating beyond the temperature at which hydrogenation begins.

In testimonywhereof we aflix our signatures.

WALTER SCHOELLER. HANS JORDAN.

o KARL soHoLLKoPF. 

